Contact arrangement for relays



y 9 D. L. BEEMA'N 2,202,729

CONTACT ARRANGEMENT FOR RELAYS Filed Sept. 3 1938 Fig.

F? .2. L a

I I 2 Inventor.

Donald LBeeman, by Hus Attorneg.

Patented May 28, 1940 PATENT OFFICE CONTACT ARRANGEMENT FOR RELAYS Donald L. Beeman, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application September 30, 1938, Serial No. 232,597

Claims.

My invention relates to improvements in contact arrangements for relays and more particularly seal-in contact arrangements especially for fault responsive relays.

In low voltage alternating current networks there are used protective relays which respond to faults to complete the circuit of a circuit breaker trip coil, and on the reappearance of normal conditions to complete the circuit of the circuit breaker closing coil. Such relays may operate many times in a day. Moreover, they are usually mounted in places inconveniently accessible for inspection and maintenance. Consequently, it is essential that they have long contact life. Also when contact is established, it must be definitely maintained until the operating cycle is correctly completed. Furthermore, where space is limited, it is necessary to obtain a desired operation without the more or less bulky seal-in magnet construction which is necessary if this magnet has to move the relay driving mechanism after contact is established. Also such a large magnet introduces an undesirable impedance in the tripping and the closing circuits.

In accordance with my invention, I provide an improved contact arrangement whereby contact, whenonce established, is definitely maintained, and whereby movement of the relay driving mechanism bythe seal-in magnet is eliminated by having the seal-in armature movable by and relatively to the relay driving mechanism. These and other objects of my invention will hereinafter appear in more detail.

My invention will be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims. 7

In the accompanying drawing Fig. 1 is a side elevation of an embodiment of my invention as applied to a relay; Fig. 2 is a top plan view of the embodiment of my invention shown in Fig. 1; Fig. 3 illustrates in perspective to a larger scale the embodiment of my invention shown in Figs. 1 and 2 and diagrammatically a circuit arrangement for use in tripping and closing of a circuit breaker; Fig. 4 is a part sectional part plan view to an enlarged scale on the line 4-4 of Fig. l, and Fig. 5 is a vertical elevation on the line 55 of Fig. 4.

In Figs. 1 and 2 I have illustrated an embodiment of my invention as applied to a relay of the type disclosed in U. S. Letters Patent No. 2,110,686, issued March 8, 1938. However, as my invention is not.limited to any particular relay .con'tact head l8.

and since the relay per se forms no part of my invention, I have shown only as much of the relay as is necessary for an understanding of the application ofmy invention. In general, the relay comprises one or more electromagnetic motor elements III which actuate a movable member shown as a shaft N. This shaft is supported at its upper end by a suitable bearing l2 which is mounted on the relay head l3. The relay shaft ll may also be biased for movement in one direction by suitable means indicated as a spiral spring H. In general, the shaft H, instead of carrying the contact directly, drives through a suitable mechanism, such as a pinion i5 and a. segmental gear [6, a contact supporting shaft ll. This contact shaft is rotatably supported on a contact head l8 by a foot bearing mounted therein and a top bearing 9. The contact head It is suitably secured to the relay head l3- While this contact head may, in general, be of any suitable material, I have found moulded insulation to be excellent for the purpose since all the desired supports, coil enclosures, etc. may be readily incorporated in a unitary structure applicable to different relays.

For supporting the movable contact or contacts, where more than one is employed, so as to be actuated upon movement of the contact shaft ii, I may mount thereon for insulating purposes suitable means shown as a moulded insulating member which so surrounds the 1 shaft as to insulate it from any of the metallic parts of the relay. Mounted on this insulating member 20 so as to be movable therewith and relatively thereto are one or more contacts 2i and 22 which are arranged to engage cooperating relatively stationary contacts 23 and 2d respectively. y

In order to insure maintenance of contact engagement once the contacts are engaged, I provide one or more seal-in magnets 25, 2E which are mounted in suitable hollow openings in the In order to conduct current to the movable contacts, I provide suitable means, such as a flexible helical lead-in 21, which is carried by the insulating member 29 and which may be guarded from contact with other metallic portions of the relay by an insulating shield 28. In order to hold the contacts in engagement once the contact is made, the magnetic circuit of the seal-in magnet, which includes spaced polar projections 29 and 38, is arranged to be bridged by suitable armature means 3! movable in accordance with my invention with the contact shaft I1 and relatively thereto so that, upon contact closing, the armature 3! may move to the attracted position without the necessity of moving any of the driving mechanism of the relay. Each armature may be provided with non-magnetic inserts 38' to prevent sticking on residual magnetism.

'One suitable arrangement whereby this may be accomplished is to have the relatively stationary contact 23 or 24 positioned in the air gap between the polar projections 29 and 30 and the cooperating movable contacts 23 and 22 so arranged that they are free to move into these air gaps to engage the stationary contacts. In order to obtain the desired relative movements of the movable contacts 2! and 22 and the armatures 3i relatively to each other and to the contact actuating shaft H, the armatures may be formed from suitable magnetic pieces having supporting arms 30' so shaped as partially to embrace the insulating member 29 on its lower rounded portion 20' just above the lower portion 32 thereof and to set into recesses defined by a rearwardly extending portion 38 and a wall portion 33. They may be retainedtherein by a suitable top supporting piece 3 1. Each movable contact may be suitably supported on a resilient strip of metal 35, such as phosphor bronze, which lies within the recessed or walled portion of the insulating member 20 between the wall 33 thereof and the armature supports 30'. The resiliency of the strip 35 and its position and shape are such as to tend to maintain the armature supports 30 against the lower rounded portion 20' of the member 20 and yet permit a limited free motion of the armature relatively to this member. Suitable connection between the movable contacts and the helical lead-in 21 may be obtained by a conductor 36, which is secured to the movable contact strip 35 by suitable fastening means indicated as a bolt 31'. vAs shown, this bolt may also serve to hold in place the retaining member 34 which prevents the armature supports 30 from working out of their supporting pockets in the insulating member 20.

In order that the movable contacts 2| and 22 may have a limited movement relatively to their supporting armatures and be definitely returned upon release of the armature, the end of the resillent supporting member 35 mayv be shaped, as

shown, so as to extend around and embrace the opposite side of the armature and yet be free :tor a limited movement relatively thereto. Since the armature supporting means 30' are shaped to have a bearing on the rounded or shaft enclosing portion of the insulating member 20 and yet have the inner ends free to pivot on the lower backwardly extending central portion 38 of the member '20, as will be more clearly apparent from Figs. 4 and 5,,it will be obvious that, upon movement of the shaft I! in one direction to the point where the contacts which are closed in this movement engage, the armature will be free to turn in the same direction to the attracted position as soon as the contacts engage without any regard to the further movement of the shaft I1. In other words, seal-in is effective upon contact engagement without the necessity of an electromagnet sufliciently strong to turn the whole relay driving mechanism whereby to move the, seal-in armature into the attracted position.-

Referring now more particularly to Fig. 3 for an explanation of the operation of my invention,

it will be assumed that in this figure the windings 39 and 4|! represent respectively the closing and tripping coils of a circuit breaker which is provided with a b auxiliary switch II and an a auxiliary switch 42. It will further be assumed that the circuit breaker is open so that the auxilrelay associated with these contacts is included in series in the circuit of the closing coil 39 and the armature 3! associated with the contact 22 caused to engage the pole pieces 29 and 30 of the seal in magnet 2d. During this action, there is a limited movement of the contact 22 relatively to the contact support 2b in a direction opposite to the movement of this support and a limited movement of the armature 3i associated with the contact 22 in the same direction as the movement of the contact support 20 independently of the action of the driving means of the relay so that the seal-in magnet does not have to do any work in moving such driving means. As is 'Well known to the art, upon the closing of the circuit breaker, the b auxiliary switch 4! opens and deenergizes the seal-in magnet whereby the contact member 29 is free to move to whatever position the energization of the relay calls for in conjunction with the bias of the spring !4.

It will be apparent that the motion of the relay in the other direction will cause a similar action with respect to the'contacts 2i and 23 and the associated armature 3| except that in this case the circuit of the trip coil 40 would be completed if the circuit breaker were in theclosed position. Thus, upon movement of the relay in either direction, a contact closing seal-in action is effected as soon as the contacts engage to energize the seal-in magnet since the armature is immediately moved to the attracted position by virtue of its mounting which provides, in accordance with my invention, for movement of the armature relatively to the driving mechanism of the relay.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a, seal-in contact arrangement for relays having a movable member and actuating means therefor, a seal-in electromagnet comprising a winding, relatively movable cooperating contacts one mounted for movement with and relatively to said member, an energizing circuit for said winding including said contacts, an armature for said electromagnet, and means resiliently supporting said armature on said member for movement therewith in circuit-closing direction and relatively thereto to the attracted position after engagement of said contacts and independently of further movement of the member.

2. In a seal-in contact arrangement for relays havinga movable member and actuating means therefor, a seal-in electromagnet comprising a winding, relatively movable cooperating contacts one mounted for movement with and relatively to said member, an energizing circuit for said winding including said contacts, and an armature for said electromagnet movable by said member in the circuit closing direction thereof and movable in said direction relatively to said 75 member to the attracted position subsequently to the closing of said contacts to maintain itself in the attracted position and the contacts in the circuit closing position independently of further movement of the member in the circuit closing direction.

3. In a relay having a movable member and actuating means therefor, a seal-in electromagnet comprising a winding, a stationary contact, a cooperating contact, means resiliently supporting said cooperating contact on said member for movement therewith and relatively thereto, an energizing circuit for said winding including said contacts, and an armature for said electromagnet mounted on said member for movement therewith and resiliently supported thereon by said contact supporting means to permit movement of the armature to the attracted position upon movement of the member in circuit closing direction and independently of the movement of the member after the engagement of said contacts.

4. In a seal-in contact arrangement for relays having a movable member and actuating means therefor, a stationary contact, a cooperating contact mounted on said member for movement therewith in one direction to engage said stationary contact and a limited movement relatively to the member in the opposite direction, a seal-in electromagnet comprising a winding and two spaced polar projections positioned with said stationary contact between them, an energizing circuit for said winding including said contacts, and an armature mounted on said movable member for movement therewith in said one direction toward said polar projections and a limited movement relatively to the member in said one direction upon engagement of said contacts to close said circuit whereby the armature is moved to and maintained in the attracted position independently of further movement of said member in said one direction.

5. In a seal-in contact arrangement for relays having a rotatable member and actuating means therefor, a seal-in electromagnet comprising a winding and two spaced polar projections, a stationary contact mounted substantially in line with said polar projections in the space between them, a cooperating contact resiliently supported on said member and movable therewith in one direction to engage said stationary contact, an energizing circuit for said winding including said contacts in series, an armature mounted on said member for movement therewith in said direction toward said polar projections and a limited movement in said direction relatively to said member upon engagement of said contacts to close saidcircuit whereby the armature is moved to-engage said polar projections and maintained in the attracted position independently of further movement of said member in said direction.

DONALD L. BEEMAN. 

